Detergent composition containing, as a builder, the sodium salt of glycerol tricitrate

ABSTRACT

Water-soluble salts of acid carboxylic acid esters of at least trivalent aliphatic or olefinically unsaturated carboxylic acids or hydroxycarboxylic acids and at least trihydric aliphatic alcohols are used as builders for detergent and cleansing agents. Each hydroxylic group of the alcohol and optionally of the carboxylic acid has a carboxylic acid-molecule attached thereto.

252-99. AU 165 EX United States Patent 11 1 1111 3,859,224 Kandler et al. Jan. 7, 1975 DETERGENT COMPOSITION [5 l] Int. Cl C0ld 3/06 CONTAINING, AS A BUILDER, THE [58] Field of Search..... 252/DlG. I. DIG. 2. DIG. 6, SODIUM SALT OF GLYCEROL 252/9 I35. 89. 526. 527 TRICITRATE R f C1 d e erences 1 e [75] Inventors: Joachim Kandler,

Erftstadt-Lechenich; Karl UNITED STATES PATENTS Merkenich, Efferen; Klaus Henning, 3 233 32 3x 2; 2 fg i Hurth; wfl l vogt Efferen; 9 entsc e 5 9 3,7l7,6l6 2/l973 Chakrabartl et al 252/89 X ig z 3,763,047 10/1973 Fairs 2521135 Erftstadt'lechenich of Germany Primary Examiner-Leland A. Sebastian [73] Assignee: Hoechst Aktiengesellschaft, Attorney, Agent, or Firm-Connolly and Hutz Frankfurt/Main, Germany 221 Filed: Sept. 21, 1972 [571 ABS TRACT Water-soluble salts of acid carboxylic acid esters of at [21] PP 2911044 least trivalent aliphatic or olefinically unsaturated carboxylic acids or hydroxycarboxylic acids and at least [30] Foreign A li fi p i Data trihydric aliphatic alcohols are used as builders for detergent and cleansing agents. Each hydroxylic group Sept. 24. l97l Germany 2147778 of the alcohol and optionally of the carboxylic acid [52] U S 252,135 252,89 252,99 has a carboxylic acid-molecule attached thereto.

252/526, 252/527, 252/DIG. l, 252/DIG. 2

4 Claims, 2 Drawing Figures DETERGENT COMPOSITION CONTAINING, AS A BUILDER, THE SODIUM SALT OF GLYCEROL TRICITRATE The present invention provides builders for detergents and cleansing agents, the builders comprising water-soluble salts of acid carboxylic acid esters, the esters being the product obtained by the reaction of at least trivalent carboxylic acids with polyhydric alcohols.

It has already been reported that the cleansing power of soaps and synthetic detergents in detergent and cleansing agents can be improved by means of certain addends. These cleansing intensifiers are termed builders. Detergent and cleansing agents having such builders therein are more effective, yet less costly than corresponding formulations which are free from builders.

The mechanism and the details of the builder effect have not yet been fully described. Vital to the function of the builder is a plurality of processes comprising, for example: the stabilization of pigment dirt suspensions; the emulsification of dirt particles; the effect on the surface and interfacial properties of aqueous tenside solutions; the solubilization of waterinsoluble ingredients of the cleansing bath; the peptization of agglomerated dirt; the neutralization of acid substances; and the inactivation of mineral matter in the cleansing bath.

To determine the quality and qualification of individ ual materials for use as a builder, it is good practice to test their behavior and efficiency in washing or cleansing operations, to ensure the qualitative and quantitative determination of all factors that make their contribution to the builder effect.

Classical builders comprise water-soluble inorganic alkali metal salts, such as alkali metal carbonates, borates, phosphates, polyphosphates, bicarbonates, and silicates.

While a plurality of mate rials have been suggested for use as builders, the fact remains that linear condensed phosphates or polyphosphates, more particularly pen- -tasodium triphosphate or sodium tripolyphosphate, are

almost exclusively used as the builders in customary detergent and cleansing agents having up to substantially 50 weight percent builder therein.

The considerably increased consumption of phosphatecontaining detergent and cleansing agents both for domestic and industrial purposes has also effected an increase in the phosphate content of natural waters. ln studies of the eutrophication of waters, which has been found to occur at increasing rates, the nitrates and phosphates have recently been held to have properties that are able under certain conditions to promote the growth of certain alga species, and thereby to make their contribution to the eutrophication of water. Even though it is impossible for the time being definitely to clarify this problem, namely the contribution of detergents and cleansing agents to the eutrophication of water, it is highly desirable to have potential substitutes free from nitrogen and phosphorus for the builders, namely polyphosphates, that find widespread use in current detergent formulations.

Compounds which are free from nitrogen and phosphorus have already been suggested for use as builders in detergents. Starch derivatives, such as dicarboxyl and carboxymethyl starch, polycarboxylic acids, such as polymaleic acid and the copolymers thereof, oxydiacetic acid, oxydisuccinic acid, esters containing sulfonate groups of polyethylene glycol and adipic acid or maleic acid, and esters of ethylene glycol and trior tetracarboxylic acids, have more particularly been used heretofore. The use of these substances as builders has been found to entail disadvantages which reside in the fact that they are insufficiently biodegradable or have an unsatisfactory power for dispersing hydrophilic dirt. Still further, there partially is a lack of processes permitting these substances to be made under commer cially attractive conditions.

In addition to the tenside constituent, which merely enables hydrophobic dirt, such as carbon black and fat particles, to be dispersed and/or peptized, it is necessary for a detergent to contain a further ingredient removing hydrophilic dirt, namely a builder. ln the ab- 1 alcohol and optionally of the carboxylic acid having a carboxylic acid-molecule attached thereto, are very suitable for use as builders in detergents and cleansing agents, as they have an efficiency excelling that of conventional builders free from nitrogen and phosphorus.

The cation of the water-soluble salts of acid carboxylic acid esters preferably is an alkali or ammonium ion, whereas the ester-type anion is based on a "Mr tetravalent carboxylic acid, which has between six and 10 carbon atoms and is esterified with a polyhydric alcohol containing between three and six hydroxylic groups.

In accordance with the present invention, the acid component of the carboxylic acid esters should be selected, for example, from the group consisting of citric acid, aconitic acid, tricarballylic acid, dihydroxytrican ballylic acid, nitrilotriacetic acid, or ethylenediamine tetracetic acid, and the alcoholic component should be selected from the group consisting of glycerol, erythritol, pentaerythritol, mannitol, sorbitol or a sugar alcohol having between four and six carbon atoms.

To produce detergent and cleansing agents, it is possible to introduce the ester salt builders of the present invention into conventional detergent and cleansing agents, which are based on ion-active and/or non-ionic tensides and which may optionally contain further addends. In accordance with the present invention, the builder may generally be used in a proportion substantially between 10 and 80 weight percent, preferably between 15 and weight percent, based on the dry substance of the detergent and cleansing agent. In addition to a water-soluble salt of acid carboxylic acid esters, the detergent and cleansing agents may contain as a further builder one or more alkali metal polyphosphates or their substitutes specified hereinabove. Detergent and cleansing agents prepared in accordance with the present invention give a pH-value substantially between 8 and 12 in the aqueous medium of the wash bath.

The addends, which may be present together with the ion-active and/0r non-ionic tensides in the detergents comprise substances, such as alkali metal or ammonium salts of sulfuric acid, silicic acid, di-and trisilicic acids, carbonic acid, boric acid, iminodiacetic acid, nitrilotriacetic acid, ethylene diamine tetracetic acid, alkylene phosphonic acids, hydroxyalkylene phosphonic acids and/or aminoalkylene phosphonic acids, or stabilizers and activators for perborates, as well as optical brighteners, carboxymethyl cellulose, magnesium silicate, disinfectants and/or enzymes, for example.

The carboxylic acid esters underlying the builder salts of the present invention are produced by conventional esterification methods, for example, by reacting the acid with the alcohol and simultaneously distilling off the reaction water by means of an expelling agent. The acid and alcohol should generally be used in a molar ratio such that one molecule of the at least trivalent carboxylic acid be available, per alcoholic hydrox' ylic group. In those cases in which the carboxylic acid itself contains one or more hydroxylic groups, it is also possible to esterify these groups. In this case, the quantitative ratio between acid and alcohol is accordingly greater than the number of the hydroxylic groups in the polyhydric alcohol. During the esterificztion, it is necessary and critical to remove from the esterification mixture 1 mol of reaction water, per mol of carboxylic acid used. The resulting acid carboxylic acid esters are transformed into watensoluble salts by the addition of stoichiometric proportions of alkali.

The builders of the present invention offer technically very beneficial effects as they considerably delay the precipitation of calcium ions in the wash bath and additionally do form stable dispersions with hydrophilic pigment particles. A further beneficial effect resides in the fact that they are readily biodegradable and thereby prevented from concentrating in natural waters.

The properties of the builders of the present invention can be evaluated, for example, by identifying their power of dispersing iron (lll) oxide, their power of binding calcium ions and their washing efficiency on washing an artificially soiled fabric. Suitable tests were made with the builders of the present invention and the results obtained were compared with the properties of conventional builders. The tests were more particularly carried out in the manner described in the following Examples.

EXAMPLE 1 The following novel builders:

A. Sodium salt of glycerol-tri-citrate B. Sodium salt of sorbitol-hexa-citrate C. Sodium salt of pentaery-thritol-tetra-citrate were tested as to their dispersing effect in an aqueous suspension of 4 weight percent of dry, pulverized iron (lll) oxide with a particle size of less than 0.058 mm, and the effect produced was compared with that produced by conventional builders, namely:

D. Trisodium citrate E. Glycerol F. Diacetin G. Sodium salt of ethyleneglycol di-citrate. Each of the builders was used in the suspension in a concentration of 0.16 weight percent, based on the aqueous solution. The settling time of the iron oxide particles in cc mixing cylinders, and the volume of sedimentation after 24 hours were determined in each case as an index of the dispersing effect. The suspension had a pH-value of 10. The results obtained are summarized in Table l below.

As can be seen from Table l, the novel builders had a dispersing effect on hydrophilic dirt particles which was better than that of conventional builders. This results from both the smaller sedimentation volume and lower settling rate.

EXAMPLE 2 The builders specified in Example I were tested as to their power of binding calcium ions. The power of binding calcium ions in an aqueous solution is defined by the number identifying the grams of calcium ions kept in solution under certain conditions, by 100 grams of builder. This number was determined by titration with sodium carbonate. More particularly, a 1 percent test solution with a pl-l-value of l0 was titrated with a 0.lN calcium chloride solution until turbidity commenced to occur. The following numerical values indicating the power of binding calcium ions were determined for the individual builders (Table 2).

As can be seen from Table 2, the novel builders were found to combine the good dispersibility of Table l with a good power for binding Ca ions. As compared therewith, conventional builders could not be found to have these two properties at the same time to the same extent.

EXAMPLE 3 Wash tests were made to determine the cleansing power quotients of wash liquors which for a constant concentration of surface active substance contained varying proportions of the builders of the present invention specified in Example 1, and the test results obtained were graphically plotted in HO. 1 of the accompanying graphs, curves A-B. Analogous wash tests with the use of the conventional builders, specified in Example l, were made for the purpose of comparison, and the cleansing power quotients were also graphically plotted in FIG. 1, curves D, F and G.

The wash tests were made on standard cotton fabrics soiled with Krefeld dirt in a Launder-O-meter at a wash bath temperature of C. Standard fabrics soiled with Krefeld dirt have been defined by Kurt Lindner in the book entitled; Tenside, Textilhilfsmittel Waschrohstoffe, Wissenschaftl. Verlags gesellschaft Stuttgart (1964), volume ll, page 1837.

The wash water had a hardness of 20 (German degrees of hardness) and a pH of 10. The wash period was 30 minutes and the bath ratio, expressed by the ratio of material to be washed in kg to wash liquor in liter was 1:50, and the wash operation was carried out in the presence of steel balls. The wash liquor contained as surface-active substances 0.45 g/liter of dodecylbenzene sulfonate,

0.15 g/liter of tallow fatty alcohol and 0.15 g/liter of hardened tallow soap.

The builders were used in the wash liquor in a concentration between 0.2 and 2 grams/liter of wash liquor.

After the prescribed wash time, the standard cotton fabric was rinsed, once hot and once cold, and its degree of whiteness was then determined using an Elrepho remission photometer, (a product of Zeiss) and a filter R 53. Based on the test result obtained, the cleansing power quotient was calculated according to the following formula:

percent WK percent WG, percent WG in which percent WK percent cleansing power,

percent WG, percent whiteness of washed fabric,

percent WG, percent whiteness of unwashed fab- As can be seen from curves A and B shown in FIG. 1, more cleansing power is imparted to the wash liquor by the builder employed in accordance with the present invention than by the conventional builders D, F and 0.

EXAMPLE 4 The procedure was the same as that described in Example 3, save that the following additional ingredients were introduced into the wash liquor;

0.l5 g of magnesium silicate/liter of wash liquor,

0.15 g of sodium silicate/liter of wash liquor,

1.25 g of sodium perborate tetrahydrate/liter of wash liquor,

0.45 g of sodium sulfate/liter of wash liquor, and

0.05 g of tylose/liter of wash liquor.

The wash results obtained were graphically plotted in FIG. 2, curves A and B. As can be seen, the builders used in accordance with the present invention were found to distinguish favorably over the conventional builders (curves D, F and G) Preparation of the builders used in accordance with this invention The builders used in Examples 1 to 4 were not specifically purified during preparation. In other words, the reaction products (crude products) directly obtained following termination of the esterification of the polyvalent carboxylic acid with the polyhydric alcohol or following neutralization of the resulting esterification mixtures, were used. This is further illustrated in the following Examples.

EXAMPLE 5 A mixture of 136 parts by weight of pentaerythritol and 768 parts by weight of anhydrous citric acid was subjected to azeotropic distillation with 250 parts by weight of toluene, which was continuously recycled, so as to remove 72 parts by weight of reaction water, which did form during the esterification. The mixture was allowed to cool and the toluene was separated from the ester. To produce the sodium salt, the acid crude ester was dissolved in 800 parts by weight of 40 percent sodium hydroxide solution and the resulting neutralization mixture was dried under vacuum. The product so obtained was used as builder C in Examples 1 to 4.

EXAMPLE 6 A mixture of 92 parts by weight of glycerol and 768 parts by weight of anhydrous citric acid was subjected to azeotropic distillation with 250 parts by weight of toluene, which was continuously recycled, so as to re move 72 parts by weight of reaction water, which did fonn during the esterification. The ester was cooled and the toluene was separated from the ester. To produce the sodium salt, the crude ester was neutralized with 800 parts by weight of 40 percent sodium hydroxide solution and the resulting neutralization mixture was dried under vacuum. The product so obtained was used as builder A in Examples 1 to 4.

We claim:

1. A detergent composition comprising an ionic or nonionic surface active agent and, as a builder, the sodium salt of glycerol tricitrate.

2. The detergent composition according to claim 1 wherein the builder is present in a proportion between 10 and weight percent based on the total dry ingredients of the composition.

3. The detergent composition according to claim 2 wherein the builder is present in an amount between 15 and 60 weight percent and the composition additionally contains an alkali metal polyphosphate builder.

4. The detergent composition according to claim 2 containing an alkali metal or ammonium salt of an acid selected from the group consisting of sulfuric acid, silicic acid, diand trisilicic acids, carbonic acid, boric acid, iminodiacetic acid, nitrilotriacetic acid, ethylene diamine tetracetic acid, an alkylene phosphonic acid, a hydroxyalkylene phosphonic acid or an aminoalkylene phosphonic acid, and additionally containing a perborate, stabilizer and activator, an optical brightener, carboxymethyl cellulose, magnesium silicate, a

disinfectant, an enzyme or mixtures thereof.

a n: s r :0: 

1. A DETERGENT COMPOSITION COMPRISING AN IONIC OR NONIONIC SURFACE ACTIVE AGENT AND, AS A BUILDER, THE SODIUM SALT OF GLYCEROL TRICITRATE.
 2. The detergent composition according to claim 1 wherein the builder is present in a proportion between 10 and 80 weight percent based on the total dry ingredients of the composition.
 3. The detergent composition according to claim 2 wherein the builder is present in an amount between 15 and 60 weight percent and the composition additionally contains an alkali metal polyphosphate builder.
 4. The detergent composition according to claim 2 containing an alkali metal or ammonium salt of an acid selected from the group consisting of sulfuric acid, silicic acid, di- and trisilicic acids, carbonic acid, boric acid, iminodiacetic acid, nitrilotriacetic acid, ethylene diamine tetracetic acid, an alkylene phosphonic acid, a hydroxyalkylene phosphonic acid or an aminoalkylene phosphonic acid, and additionally containing a perborate, stabilizer and activator, an optical brightener, carboxymethyl cellulose, magnesium silicate, a disinfectant, an enzyme or mixtures thereof. 